An amazing chart on how the Koch brothers are dominating the Senate ad race

There has been much hand-wringing over the past 48-72 hours about predictions that Republicans are now favored to take over the Senate in November.

There have also been plenty of warning signs being thrown up by Democratic leaders, from top strategists to President Obama.

The chart below, from Kantar Media Intelligence/CMAG, explains both of these about as clearly as possible.

As you can see, not only are Democrats defending very red states; they are getting clobbered on the airwaves early this election year.

The GOP outside group Americans for Prosperity, backed by the Koch brothers, David and Charles, has been far outspending the top Democratic super PACs in nearly all of the Senate races the GOP is targeting this year.

The difference in seven of the nine races (not counting the now-concluded Massachusetts special election) is at least two-to-one, and the Democratic super PACs have had virtually no air presence in five of the nine states.

Given the terrain and the early spending, it's not hard to see why Republicans are looking like they could very well win the six seats they need to re-take the Senate.

This isn't the complete picture of all outside spending, of course, but these are the dominant players on that front, so it's a pretty good approximation of where the ad war stands in most states.

Update 11:16 a.m.: On that point -- Democrats note that, despite the comparison above, their side has actually spent more in Alaska than Republicans have. Another Democratic group, Put Alaska First PAC, has actually spent almost as much as AFP. AFP is still the top spender there, though.

The question from here is whether Democrats can get anywhere close to parity, and whether AFP's early ads -- met in most cases without virtually any Democratic response -- have changed the 2014 election in some lasting way.